Léo Siqueira Ph.D. Meteorology and Physical Oceanography

Transcription

1 Léo Siqueira Ph.D. Meteorology and Physical Oceanography

2 Modular Ocean Model (Griffies 2009) from GFDL version MOM4p1: Includes the Sea Ice Simulator (SIS) built-in ice model (Winton 2000). Includes TOPAZ built-in Global physicalbiogeochemical model.

3 Horizontal grid resolution: 1/4 in the tropical region decreasing uniformly towards the poles. Tripolar grid to avoid computational issues at north pole due to meridians clonfluence. Vertical grid: 50 levels with a 10- m resolution in the upper 220 m, increasing gradually to about 370 m of grid spacing at deeper regions.

4 ESM modeling Atmospheric convection/precipitation, boundary layer stability and gustness strongly affect the ocean model in coupled mode. Needs precise adjustment of key factors depending on the grid setup and chosen parameterizations. Main goal is to simulate annual cycle correctly and SST anomalies for different time-scales. Adjustment/improvements in uncoupled mode may not work the same way as in coupled mode. Better to work as a whole coupled system (ESM) instead of considering separate components (AGCM, OGCM, LAND, ICE).

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6 Strong link between rainfall anomalies over Brazil and sea surface temperature anomalies in the tropics. ENSO Impacts Tropical Atlantic Variability

7 Interannual climate variability: BESM shows a robust ENSO signal over the equatorial Pacific Ocean, with peak energy in the 3 to 5 year range, in agreement with observations.

8 BESM shows a dipole-like pattern of SST and surface winds with peak energy on the decadal scale in the Atlantic Ocean, in agreement with observations.

9 BESM shows important atmospheric teleconnections, like the PSA pattern of positive and negative 500-hPa height anomalies that influences precipitation over South America in agreement with observations.

10 BESM Sea-Ice Extent BESM Sea-Ice model simulates the reduction in sea-ice extent in the last decades.

11 BESM Topaz Ocean CO2 Sources/Sinks DJF NECC CO2 Sink due to advected Amazon River water JJA Amazon river runoff and its CO2 Sink De Farias et al (2012)

12 BESM-OA2.3_Topaz Ocean Nitrate TOPAZ OBSERVATION Congo river Nitrate Runoff Congo river Nitrate Runoff De Farias et al (2012)

13 Land-Ocean coupling: River inflow effects on ocean circulation and salinity MOM3 w/o river discharge MOM4 with river discharge Amazonas river runoff carried by NECC

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15 Climate Change Ocean Heat content and Atmospheric CO2 concentration. The essential balance in the Earth System is between total OHC (the primary heat storage term) and FTOA (the total energy flux entering or leaving the system).

16 +0.3W/m yr trend in: (a) full depth Ocean Heat Content Anomaly (b) top-of-atmosphere radiation flux imbalance

17 Mauna Loa CO2 Increase Global SST increase. Time-depth profile of ocean temperature.

18 RCP4.5 an RCP8.5 OHC increase. Sea-ice extent reduction Sea-ice extent reduction (No annual cycle)

19 December September Mauna Loa RCP 8.5 Mauna Loa RCP 8.5

20 Sea Level Rise BESM simulates sea level rise due to ocean thermal expansion and fresh water inflow. What is BESM missing regarding sea level rise?

21 Sea Level Rise What is missing? Thermal expansion effect in sea level. Fresh water inflow effect in sea level

22 Sea Level Rise Missing Component: Land Ice model

23 Sea Level Rise, Others?

24 Current Challenges: Improving simulation of ocean temperatures (specially in the tropics) and sea-ice. Creating a healthy discussion about Land-ice model development in BESM at CONCLIMA 2013.

25 Future Challenges: Moving towards high resolution simulations: (10km ocean 50km atmos) Needs adequacy of ocean model towards 10km grid and atmospheric model towards 50km grid. Resolution often portrayed as the solution to everything -> untrue and new problems arise, for example: Increase in heat transport due to eddies and changes in the mean circulation makes high-resolution simulations ubiquitously warmer than the low-resolution simulations.

26 Future Challenges: The largest differences are in the Arctic with notable losses of sea-ice and in regions of relatively large ocean eddy activity (i.e., Southern Ocean and western boundary currents). Warming involves an ice-albedo feedback in the polar latitudes, changes in cloud cover in the western boundary current regions and global water vapor in the tropics and sub-tropics. How does this all change in future cenarios?

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